A very unstable air mass was in place with temperatures in the 90s and dew points in the upper 70s. While forcing was weak, there was enough lift ahead of a mid-level impulse to spark widespread convection in the form of a mesoscale convective system.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS ILN wrote it up.
A very unstable air mass was in place with temperatures in the 90s and dew points in the upper 70s. While forcing was weak, there was enough lift ahead of a mid-level impulse to spark widespread convection in the form of a mesoscale convective system.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Wilmington, OH wrote its last area forecast discussion before the first event at Aug 4, 9:14 AM EST, 1 hour 57 minutes earlier.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
1014 AM EDT WED AUG 4 2010
.SYNOPSIS...
A FRONTAL BOUNDARY WILL DRAPE WEST TO EAST OVER THE OHIO VALLEY
TODAY AND SLOWLY ORIENT ITSELF ALONG THE OHIO RIVER TONIGHT AND
THURSDAY. THIS WILL BE A FOCUS FOR SHOWER AND THUNDERSTORM
ACTIVITY THROUGH THURSDAY NIGHT. HIGH PRESSURE WILL THEN BUILD
OVER THE UPPER MIDWEST AND GREAT LAKES REGION...PROVIDING DRIER
CONDITIONS FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
REMNANTS OF OVERNIGHT MCS CURRENTLY PUSHING ACROSS NORTHERN
INDIANA. THE SOUTHERN EDGE OF THE LEADING BOW ECHO HAS SHOWN SOME
REGENERATION DURING THE PAST HOUR OR SO. THIS IS IN AN AREA OF
BETTER INSTABILITY WITH ML CAPES CLOSE TO 3000 J/KG THAT EXTENDS
SOUTHEASTWARD TOWARD DARKE COUNTY. AS A RESULT...THINK WE MAY SEE
SOME SOUTHWARD DEVELOPMENT WITH THIS AS IT CONTINUES TO PUSH EAST
THROUGH LATE MORNING. WILL MAKE SOME TWEAKS TO THE FORECAST TO
RAISE POPS ACROSS THE FAR NORTH WITH THIS. OTHERWISE...AIRMASS
WILL DESTABILIZE ACROSS THE REMAINDER OF OUR FA THROUGH EARLY TO MID
AFTERNOON AS TEMPS CLIMB INTO THE UPPER 80S/LOWER 90S WITH
DEWPOINTS INTO THE 70S. MORNING ILN SOUNDING HAD AN 850 MB
TEMPERATURE OF 22.2 DEGREES WHICH WOULD SUPPORT A HIGH INTO THE
MID 90S FOR THIS AFTERNOON. HOWEVER...AM A BIT CONCERNED WITH THE
EFFECTS THAT AN OUTFLOW BOUNDARY FROM ONGOING CONVECTION UP ACROSS
NORTHERN INDIANA COULD HAVE ON TEMPS...ESPECIALLY ACROSS NORTHERN
PORTIONS OF OUR FA. WILL THEREFORE JUST NUDGE UP TEMPS A BIT AND
HOLD OFF ON EXTENDING HEAT ADVISORY ANY FARTHER NORTH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
WEST TO EAST ORIENTED BOUNDARY THIS EVENING WILL THEN BECOME
SITUATED MORE ALONG THE OHIO RIVER AS AN UPPER LOW PUSHES ENERGY
INTO THE GREAT LAKES AND EASTWARD. THIS WILL PERMIT HIGH PRESSURE
TO BUILD TO THE NORTHWEST AND FOR A NORTHWEST FLOW ALOFT TO HELP
KEEP SOMEWHAT DRIER AIR HOLD SWAY AFTER THE FRONTAL PASSAGE
THURSDAY NIGHT.
DID NOT MAKE ANY SWEEPING CHANGES TO THE FORECAST AND THOUGHT THAT
ANY ACTIVITY WOULD END QUICKLY THURSDAY EVENING...BY LATE
AFTERNOON FOR THE NORTHWEST HALF OF CWA.
TEMPS WILL STILL BE AT OR JUST ABOVE NORMAL BUT THE DECREASE IN
HUMIDITY WILL BE A WELCOME FEATURE FOR A CHANGE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
MUCH DRIER AND SOMEWHAT COOLER CONDITIONS WILL SETTLE IN BEHIND
THE FRONT...AS MODELS AGREE ON SURFACE HIGH PRESSURE BUILDING IN
FROM THE NORTH TO PROVIDE A PLEASANT WEATHER WEEKEND. AS THE HIGH
SLIDES EAST...SOUTHERLY FLOW WILL PICK BACK UP UNDER THE MID LEVEL
RIDGE...WHICH WILL ALLOW FOR HEAT AND HUMIDITY TO BUILD BACK IN
EARLY IN THE WEEK. WILL GRADUALLY RAMP THINGS BACK UP TO THE UPPER
80S AND LOWER 90S BY TUESDAY. THESE VALUES WERE PRIMARILY DERIVED
FROM THE MORE STABLE ECMWF WITH SOME BIAS ADJUSTMENT...AS GFS
TEMPERATURES ARE CONSISTENTLY UNREALISTICALLY WARM BY A SOLID 5
DEGREES.
ECMWF AND GFS ARE BOTH INDICATING SOME LOW CHANCES OF PRECIPITATION
AT VARIOUS TIMES ON MONDAY AND TUESDAY. NOT SEEING A STRONG SIGNAL
IN TERMS OF PLACEMENT OR TIMING HERE ON THE SMALLER SCALE...THOUGH
THE SYNOPTIC FEATURES ARE RELATIVELY SIMILARLY DEPICTED WITH A MID
LEVEL RIDGE PUSHING THE PRIMARY FORCING NORTH OF THE AREA. AT THIS
TIME WILL LEAVE PRECIP OUT OF THE FORECAST...WITH THE ASSUMPTION
THAT AT SOME POINT EARLY IN THE WEEK...POPS WILL HAVE TO BE ADDED.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
LATEST STLT AND RADAR DATA SHOW THAT MCC IS WELL E OF TERMINALS
AND MOVING AWAY. LOOKING WEST...THE NEXT SYSTEM IS WELL ON ITS WAY
WITH SHWRS AND TSTMS EXTENDING FROM NW IL BACK ACRS NRN KS. THIS FEATURE
BEGINS TO MOVE INTO OH ARND 16Z. THUS HAVE UPDATED FORECAST TO
ACCOUNT FOR THIS USING CB FOR TIMING OF TSTMS. KCVG WILL BE ON THE
SRN EDGE AND WOULD NOT BE SURPRISED IF TIMING IN TAF IS A LITTLE EARLY.
THE COMBINATION OF WK COOL FRONT DRIFTING THROUGH THE AREA
WEDNESDAY NIGHT AND INTO THURSDAY ALONG WITH WEAK UPR LEVEL
IMPULSES MOVING THROUGH WILL PRODUCE SHOWERS AND WIDELY SCATTERED
CLUSTERS OF TSTMS THROUGH THE FORECAST PERIOD. THE ONLY EXCEPTION
WILL BE THIS MORNING AFTER 12Z AND ANOTHER SHORT BREAK FOR KCVG
AND KLUK EARLY THIS EVENING.
THE LATEST NUMERICAL GUIDANCE IS INDICATING MOST OF THE ACTIVITY
MAY BE SOUTH OF KDAY AND KCMH BY 05Z. HOWEVER, BASED ON CURRENT
TREND...THE MOVEMENT OF THESE COMPLEXES OVER THE PAST FEW DAYS
NEED TO SEE ANOTHER RUN BEFORE THE FORECAST IS CHANGED.
WIND WILL BE FROM THE SW WITH SOME GUST APPROACHING 20KT THIS
AFTERNOON.
OUTLOOK...THUNDERSTORMS POSSIBLE THROUGH THURSDAY EVENING.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR OHZ060>064-
070>073-077>082-088.
KY...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR KYZ089>100.
IN...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR INZ050-058-059-
066-073>075-080.
&&
SYNOPSIS...FRANKS
NEAR TERM...JGL
SHORT TERM...FRANKS
LONG TERM...HATZOS
AVIATION...HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE WILMINGTON OH 1047 AM EDT WED AUG 4 2010 OHZ026-034-035-042>046-051>056-065-051500- HARDIN-MERCER-AUGLAIZE-DARKE-SHELBY-LOGAN-UNION OH-DELAWARE-MIAMI- CHAMPAIGN-CLARK-MADISON-FRANKLIN OH-LICKING-FAIRFIELD- 1047 AM EDT WED AUG 4 2010 ...SEVERE THUNDERSTORM WATCH 566 IN EFFECT UNTIL 4 PM EDT THIS AFTERNOON... THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL OHIO...MIAMI VALLEY OF OHIO AND WEST CENTRAL OHIO. .DAY ONE...TODAY AND TONIGHT. PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS. SEVERE THUNDERSTORM WATCH. A FRONTAL BOUNDARY WILL BE THE FOCUS FOR SHOWERS AND THUNDERSTORMS TODAY. STRONG WINDS AND HEAVY RAINFALL WILL OCCUR WITH SOME OF THESE STORMS. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE ENCOURAGED TO RELAY THEIR REPORTS TO THE NATIONAL WEATHER SERVICE. OHZ074-051500- HOCKING- 1047 AM EDT WED AUG 4 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL OHIO. .DAY ONE...TODAY AND TONIGHT. A FRONTAL BOUNDARY WILL BE THE FOCUS FOR SHOWERS AND THUNDERSTORMS TODAY. STRONG WINDS AND HEAVY RAINFALL WILL OCCUR WITH SOME OF THESE STORMS. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE ENCOURAGED TO RELAY THEIR REPORTS TO THE NATIONAL WEATHER SERVICE. INZ050-058-059-066-073>075-080-KYZ089>100-OHZ060>064-070>073-077>082- 088-051500- WAYNE-FAYETTE IN-UNION IN-FRANKLIN IN-RIPLEY-DEARBORN-OHIO- SWITZERLAND-CARROLL-GALLATIN-BOONE-KENTON-CAMPBELL-OWEN-GRANT- PENDLETON-BRACKEN-ROBERTSON-MASON-LEWIS-PREBLE-MONTGOMERY-GREENE- FAYETTE OH-PICKAWAY-BUTLER-WARREN-CLINTON-ROSS-HAMILTON-CLERMONT- BROWN-HIGHLAND-ADAMS-PIKE-SCIOTO- 1047 AM EDT WED AUG 4 2010 ...HEAT ADVISORY IN EFFECT UNTIL 8 PM EDT THIS EVENING... THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL INDIANA...SOUTHEAST INDIANA...NORTHEAST KENTUCKY...NORTHERN KENTUCKY...CENTRAL OHIO...MIAMI VALLEY OF OHIO...SOUTH CENTRAL OHIO AND SOUTHWEST OHIO. .DAY ONE...TODAY AND TONIGHT. PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS. HEAT ADVISORY. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.
The Cincinnati radar (KILN), 128 km away, was scanning. The volume nearest the first event began at 16:11 UTC.
35 thunderstorm wind, 4 hail. Local standard time, as filed.
Two power poles were reported down due to damaging thunderstorm winds.
Damaging thunderstorm winds resulted in several barns being damaged or destroyed, several silos with major damage or destruction, trees down, and an old brick school being destroyed.
Numerous trees were reported down in the southern half of the county.
Trees were reported down due to damaging thunderstorm winds.
Large trees were snapped due to damaging thunderstorm winds.
A tree was reported down due to damaging thunderstorm winds. Power lines and several large branches were also reported down around the area.
Several large tree limbs were reported down due to damaging thunderstorm winds.
Two tractor trailers were blown over and shingles were ripped off of a house due to damaging thunderstorm winds.
Trees were reported down due to damaging thunderstorm winds.
Minor structural damage occurred due to damaging thunderstorm winds.
Trees were reported down due to damaging thunderstorm winds.
A microburst hit an egg facility causing the collapse of three large barns and damaging another. This resulted in the fatalities of two men working in one of the collapsed structures. A large rooftop air conditioning unit was also pushed off the roof of an adjacent administrative building. Around the area there were several trees down and numerous broken limbs. In addition to the fatalities, four injuries were also reported.
Large branches were reported down due to damaging thunderstorm winds.
The wind gust was estimated.
Trees were reported down due to damaging thunderstorm winds.
Large limbs were reported down in addition to several large trees and power poles. Half inch hail was also reported in the area.
Several large limbs were reported down due to damaging thunderstorm winds.
Trees and branches were reported down due to damaging thunderstorm winds.
Several trees were reported down due to damaging thunderstorm winds. One of the trees fell onto a house.
Trees were reported down due to damaging thunderstorm winds.
Several trees were reported down across the county.
Trees were reported down and metal roofing was off of a shed due to damaging thunderstorm winds.
Trees were reported down due to damaging thunderstorm winds.
Trees were reported down due to damaging thunderstorm winds.
Trees were reported down due to damaging thunderstorm winds.
A tree fell onto a house due to damaging thunderstorm winds.
A tree was reported down due to damaging thunderstorm winds.
A tree was reported down due to damaging thunderstorm winds.
Large limbs were reported down due to damaging thunderstorm winds.
Trees were reported down due to damaging thunderstorm winds.
As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.
| Event | Date | Age | Sex | Where | Kind |
|---|---|---|---|---|---|
| Thunderstorm Wind, Licking | 2010-08-04 | 33 | Male | Long Span Roof | Direct |
| Thunderstorm Wind, Licking | 2010-08-04 | 25 | Male | Long Span Roof | Direct |
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Ohio in 2010Every state in 2010This day in weather historyWarnings in Ohio, August 2010
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 243558, 243568, 243570, 243574, 245146, 245155, 245148, 245150, 245156, 245152, 245153, 245154, 245159, 245151, 245164, 245161, 245165, 245158, 245160, 245157, 245162, 245167, 245168, 245163, 245166, 245172, 245170, 245169, 245174, 245173, 245171, 245176, 245177, 245179, 245180, 245178, 245181, 245182, 245183.